Oxidative metabolism of mescaline in the central nervous system—V

3,4,5-Trimethoxy-benzoic acid (3,4,5-TMBA) besides 3,4,5-trimethoxy-phenylacetic acid (3,4,5-TMPAA) is formed from mescaline during its incubation with preparations of different mouse tissues. Brain has the highest capacity to form 3,4,5-TMBA among the tissues so far studied. The enzyme system which catalyses the oxidative deamination of mescaline to 3,4,5-TMBA is localized in the nuclear and microsomal fractions of brain. Oxygen, NAD(P)H and unidentified factors of the high speed supernatant of brain extract are necessary for optimal reaction conditions. 3,4,5-TMBA formation was inhibited by SKF 525-A, but not by MAO and DAO inhibitors. The similarities and dissimilarities of the enzymic deamination of amphetamine and mescaline are discussed.